Current semiconductor packaging technology often involves tradeoffs between ease and efficiency of manufacturing on the one hand, and various performance drawbacks on the other. For example, lead-frame based packages such as quad flat no-lead (QFN) packages employ lead-frames to facilitate the packaging and singulation of multiple units at once.
The lead-frame approach is desirable due to the reduced cost, but the close proximity of solder contacts has lead to fabrication problems due to solder shorts. The contact reliability is reduced if the packages must be removed to repair solder shorts.
However, lead-frame based packages, whose connectors are typically placed either on or extending from the sides, tend to have larger footprints than ball grid array (BGA) packages, whose solder ball connectors lie directly underneath the package. Unfortunately, BGA packages have drawbacks as well. Specifically, such packages often employ laminate substrates rather than uniform metal lead-frames, making them more expensive to produce than lead-frame based packages, and less efficiently manufactured.
It is therefore desirable to design packages that employ lead-frames for ease and efficiency of manufacture, but that also have BGA-type solder ball connectors for reduced footprint sizes. In light of the increased requirements for package cost and reliability, it is further desirable to improve various aspects of the design and manufacture of these packages.
An aspect of the prior art designs is a tendency for the leads or contacts to become loose and pull out of the package. In some cases, the contact may become free of the package molding material and form cracks that can make for unreliable contacts. These issues may show up as manufacturing yield problems or early life failures of the circuit package.
Thus, a need still remains for an integrated circuit packaging system with leadless contacts for increased reliability of connection without rework risk. In view of the demand for packages having a high density of contact connections, it is increasingly critical that answers be found to these problems. In view of the ever-increasing commercial competitive pressures, along with growing consumer expectations and the diminishing opportunities for meaningful product differentiation in the marketplace, it is critical that answers be found for these problems. Additionally, the need to reduce costs, improve efficiencies and performance, and meet competitive pressures adds an even greater urgency to the critical necessity for finding answers to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.